Stunted growth in fish

fishiefishfish said:

I've heard that over stocking an aquarium can lead to stunted growth in fish. Is this permanent, or will the fish continue to grow when the tank population has diminished? Is the effect the same on all freshwater aquarium dwellers or does it change between fish (tetras and plecos specifcally) , snails and shrimp?

Any advice would be much appreciated!

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Stunted growth means the fish cannot develop properly internally (organ development) because of some environmental factor. While too small a space for the species is the most common cause, this can also occur from too many fish, or insufficient fish of the species, or the wrong combination of fish species. All of these affect water quality just as too small a space does, and cause stress.

It applies to all fish, and it cannot be reversed. The fish so affected will have a shorter than normal lifespan, and along the way be subject to other issues that a healthy fish would be able to fight off. One of these is usually the cause of death.

I know nothing of how this affects, or if it does, invertebrates like snails and shrimp.

You might find some more info in my article on stress, here:
http://www.tropicalfishkeeping.com/...icles/stress-freshwater-aquarium-fish-188673/

Byron.

rexpepper651 said:

is it true the size of the fish will be stunted but the insides of the fish will continue to grow cause it to have a poor life span?

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The fish cannot grow externally, meaning the physical size getting larger, because of the tank size which affects not only the physical space but the water quality [more below]. The internal organs however continue to grow, but when this is impeded by the physical limitations because the fish is not getting larger in size, the organs become deformed, and this causes the health issues that weaken the fish (immune system, etc) and will almost inevitably kill the fish at some point.

On the tank size and water, we know this is a critical relationship because discus fish breeders can raise many more fry in smaller tanks solely by doing 100% water changes 2 or 3 times every day. If these are not done, the fry will not develop properly due to the water conditions which are caused by too many fish in so small a space.

Byron.